Dell N1100-ON, Reference Manual

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Layer 3 Routing Commands
1255
Default Configuration
No subnets are associated with a BGP listen subnet range, and the BGP
dynamic neighbor feature is not activated.
Command Mode
Global Config mode
User Guidelines
This command is used to configure numbered extended community lists.
Extended community attributes are used to filter routes for VRFs. All the
standard rules of access lists apply to the configuration of extended
community lists. The route target (RT) and site of origin (SOO) extended
community attributes are supported by the standard range of extended
community lists.
Once the first permit/deny clause has been entered for a community list,
subsequent permit/deny clauses with the same list identifier are appended to
the end of the list.
Expanded community list and regular expressions are not supported.
Route Target Extended Community Attribute
The route target (RT) extended communities attribute is configured with the
rt keyword. This attribute is used to identify a set of sites and VRFs that may
receive routes that are tagged with the configured route target. Configuring
the route target extended attribute with a route allows that route to be placed
in the per-site forwarding tables that are used for routing traffic that is
received from corresponding sites.
Site of Origin Extended Community Attribute
The site of origin (SOO) extended communities attribute is configured with
the soo keyword. This attribute uniquely identifies the site from which the
provider edge (PE) router learned the route. All routes learned from a
particular site must be assigned the same site of origin extended community
attribute, regardless if a site is connected to a single PE router or multiple PE
routers. Configuring this attribute prevents routing loops from occurring
when a site is multi-homed. The SOO extended community attribute is
configured using a route map in both outbound and inbound directions. The
SOO should not be configured for stub sites or sites that are not multi-homed